Positioning devices of this type are often used in servo track writers (STW), where the tracks for magnetizable hard disks are formatted or written. For this purpose, a positioning device in the STW swivels a shaft, to which a swivel arm is attached. At its end, a write head is provided which is ultimately moved by the swivel motion of the shaft and is positioned in a highly precise manner, so that as many tracks as possible per unit surface area of the hard disk can be configured. The number of tracks formatted per surface area unit or diameter unit (tracks per inch) is a measure of the storage capacity of hard disks. For this reason, efforts are constantly undertaken to achieve a track allocation that is as tight as possible. For a hard disk manufacturer to be able to provide hard disks with a dense track allocation in an economical manner, it must be possible to position the swivel arm of the STW in an exact manner within a very short time (seek and settle time).
German Published Patent Application No. 10 2004 030 500 describes a positioning device, which has a swivel motor in the form of a so-called voice coil motor, whose primary part is formed as a rotor that is able to swivel opposite fixed permanent magnets. To activate the swivel motor, the rotor has to be supplied with electric current. For this purpose, a cable is usually provided for the electrical connection of the rotor to a stationary unit. Such a cable may interfere in a very short time with the operational behavior, especially with the exact positioning of the swivel arm of the STW.